Answer
The carbon forms 4 bonds, a double bond with each Oxygen.
Work Step by Step
1) Count the number of valence electrons. There are 16 electrons.
2) Make double bonds and count the number of electrons involved in the double bond. There are 8 electrons and 8 electrons are left.
3) The remaining electrons are placed on Oxygens as lone pairs. There are two lone pairs on each oxygen.